178 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



" Granny " Crabs). If a male, it will probably cast once 

 in two years. 



First Year. 



Number of Casting 

 Width in mm. .. 

 Width in inches . . 



1 



2 



3 



4 



5 



6 7 



4-75 



5-75 



8-5 



10-75 



145 



19-5 24-5 



a) 



(I) 



(*) 



(I) 



(I) 



(i) (i) 



8 

 30-75 



(1» 



Second Year. 



Third Year. 



Number of Casting 



Width in mm 



9 

 36-5 



(1« 



10 

 45-75 

 (If) 



11 

 565 



m 



12 

 70-6 



Width in inches 



(2|) 





Fourth Year. Fifth Year. Sixth Year. 



Number of Casting 

 Width in mm. 

 Width in inches ... 



14 

 110-0 



m 



Did not cast 



Seventh Year. Eighth Year. Ninth Year- 



Number of Casting- 

 Width in mm 



Width in inches 



15 



137-5 



(5» 



Did not cast 







16 

 ! 171-8 

 (6|) 



Tenth Year. Eleventh Year. Twelfth Year. 



Number of Casting 

 Width in mm. 

 Width in inches .., 



Did not cast 



17 

 214-7 



W) 



The approximate calculations given above do not 

 lend support to Williamson's statement that " a crab of 

 four and a quarter inches across would be not less than 

 three years, nor probably more than four years old.'' 

 Even if we take a growth ratio of one-third, which is 

 rather high, we find that the crab would not reach the 



